Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Holography techniques can be used to record holograms representing images of an object and reconstruct the images from the recorded holograms. A hologram can be defined as a pattern of intensities formed when an electromagnetic wave scattered by an object interferes with a coherent reference beam. In practice, lasers may be used to record holograms by capturing onto a recording medium both the scattered laser beam off the object as well as the original reference beam. The result of the differing phases and intensities of the two light fields combine at the hologram plane to create an interference pattern (or a fringe pattern), which defines the hologram.
Computer-generated holography (CGH) applies the above theory of holography to model a virtual holographic image through the use of a computer. For example, a computer calculates a holographic fringe pattern that is then used to set the optical properties of a spatial light modulator (SLM), such as a liquid crystal microdisplay. The SLM then diffracts the read-out light wave, in a manner similar to a conventional hologram, to yield the desired optical wavefront.
Compared to conventional holography, CGH has some advantages in that it does not rely on the availability of specific holographic recording materials and can generate three-dimensional images of nonexistent objects. However, similarly to the conventional holography, the holographic fringe pattern may be calculated based on properties of a laser beam that is used to replay the CGH. This makes it difficult to synthesize a three-dimensional image that can be displayed on various display units with laser light sources with different properties.